1. Field of the Invention
The present invention relates to a capsule type medical device system which observes the inside of a living body, and in particular, which shifts within the body while applying electrical stimuli to living body tissues, and which is capable of observing a desired site.
2. Description of Related Art
As methods by which a person who is to be investigated may check the state of his own health, for example, from the past, there have been generally known methods for performing various types of checks by human examination or by endoscopy or the like. Furthermore, there is a known method of investigation with a capsule type medical device, in which a testing module which is formed as a capsule is swallowed and is ingested to within the living body, so that his state of health can easily be checked. There have been various sorts of proposal for this kind of capsule type medical device, and, as one thereof, there is, for example, a known type of capsule type medical device of an electrically propelled type, which shifts within the living body by applying a local electrical stimulus via an electrode to living body tissue, thus taking advantage of the shrinking action of such electrical stimulation upon living body tissue (for example, refer to International Publication No. WO 01/08548).
Normally, when such a capsule type medical device is ingested to within the living body, it shifts naturally along his alimentary canal due to the peristaltic movement within, for example, his small intestine, by contrast, by applying local electrical stimuli to the living body tissue, this type of electrically propelled capsule type medical device is able, by performing shrinkage operation upon the living body tissue which is different from the peristaltic movement, to encourage its shifting along the direction of progress, or to perform shifting in the opposite direction to the direction of progress. Therefore, it is possible to perform observations with high efficiency, since it is possible to perform detailed observation by arriving quickly at the desired site for observation, and by lingering for some time at the same position.